The invention relates to a microfilm camera comprising a suction plate which is provided for holding a sheet of film and which can be moved in steps across a picture gate.
With this type of camera it is necessary, in order to achieve a high degree of picture sharpness, that the suction plate, which is movable parallel to the picture gate, should hold the front of the film sheet in the plane of the contact surfaces of the picture gate in every position of exposure.
However, this requirement cannot be fulfilled satisfactorily even with the smallest manufacturing tolerances.
In a known microfilm camera (British Patent No. 1,051,541) the roll film, which is movable in steps from a supply spool to a winding spool, can be sucked alternately by the suction chamber of the rear wall during each exposure process and by the suction chamber of the transporting plate during each film transport. Due to the fact that the film is sucked during the exposure process to the rear wall, the operator is forced to pay constant attention to changes in the thickness of the film that might occur. In a microfilm camera using sheet film, the complete release of the film sheet from the suction plate and its renewed suction furthermore involves the danger of the film sheet being displaced relative to the suction plate.